Often, sight deceives us, and we see something that does not really exist. This is explained by optical illusions – errors of visual perception. People have long learned to overcome them and even use them. And, I must say, much succeeded in this.

GAMES WITH COLOR

Perception errors characteristic of the human eye, were able to correct even the ancient architects, when they created different architectural forms. Optical illusion is often associated with the choice of the observation point, features of the surrounding background, or illumination. To correct the distortion, the masters resorted to optical corrections at the design stage of the structure. They deliberately violated the geometry of the structure: they changed the proportions, deflected elements from the vertical or horizontal, bent their contours, etc. With the help of such techniques, architects managed to “outwit” their sight. Sometimes, on the contrary, optical illusions were specially created and strengthened. It is believed that the Greeks, who learned to give architectural forms a special plasticity and expressiveness, succeeded most of all in this art.

It has long been noticed that light objects on a dark background seem larger than they actually are, and dark objects on a light one, on the contrary, appear smaller. In optics, this phenomenon is called irradiation *. Roman architect and engineer Mark Vitruvius, who lived in the I century BC, figuratively expressed its essence as follows: when combined with dark and light, the light “devours” the darkness. Indeed, in a white dress a person looks fuller than in black, and the branches of trees in the rays of the sun are noticeably “thinner”.

Familiar with this illusion, the architects of ancient Greece went to the trick – they made columns of their buildings of different thickness. An example of this is the famous Parthenon – the main temple of the Athenian Acropolis, built in 447-438 BC. Its creators, architects Iktin and Kallikrat, took into account that for the corner columns the background will be the bright sky of Hellas, and for the rest – the dark background created by the sanctuary of the temple. Therefore, they made the corner columns wider and reduced the distance between them and the neighboring columns. Thanks to these “corrections” from afar, all the columns looked exactly the same, and the difference between them was found only in direct measurement.

The picture of the Parthenon fixed another optical illusion: when the eye “slides” along the colonnade, the space filled with it visually lengthens, making the building seem larger. For the same reason, we tend to exaggerate the size of buildings decorated with ornaments and sculptural compositions.

DIRECT OR CURVED?

Ancient Greek architects knew that the vertical and horizontal straight lines with a considerable length do not seem to be parallel. So that the columns of the building did not visually disperse, when they were installed on the base (stylobate) they were slightly tilted inwards, then, as Vitruvius noted, the construction looked as solid and solid as a monolith. So that the columns did not seem concave, they were slightly thickened at a third of the height. This method was called “entasis” from the Greek word entasis – tension, gain. In addition, the columns were narrowed up (as the architects say, drowned), visually extending them and making them less massive.

The effect of “sagging” of horizontal lines was fought with the help of another technique – the curvature of the straight lines, or curvature, from the Latin curvatura – bending, curvature. Thus, the steps of the Parthenon were slightly curved, and the building itself stood on a convex stone platform – thus the illusion of the “sagging” of the floor was smoothed out. The horizontal beam (architrave) lying on the capitals of the columns in the central part was narrower than at the edges, and from a distance it looked absolutely even.

Probably, such secrets were known not only to the ancient Greeks. For example, the builders of Stonehenge (the oldest stone building in England) made the surface of a convex from various sides when processing stones. Thanks to this form, the joints of stone pillars and slabs laid on them are visually straightened (the illusion of their perpendicularity arises), and the stones themselves appear rectangular.

Optical illusions were familiar and Russian architect. One example is the Trinity Cathedral in the Trinity-Sergius Lavra, built in 1422 over the coffin of St. Sergius of Radonezh. Its outer walls have a noticeable slope to the center of the building, which enhances the impression of stability of the building. The dome-supporting drum with tapered windows tapers upward. This technique visually pulls the temple, and it looks higher than it actually is.

Another illusion arises in the Orthodox church: inside it seems to be much higher than it actually is. This effect is achieved not without the help of optical corrections. During the construction of the Trinity Cathedral, for example, were tilted inside the wall above the arches of portals and pillars that serve as pillars (pylons). Steep lines of arches and arches create an even greater effect of height.

ACCORDING TO THE LAW OF PROSPECTS

During the construction of monumental buildings, most often architects had to contend with an apparent distortion of their size with a change in distance, that is, in perspective. If, for example, to look at a tall building from the bottom up, one gets the impression that at the top it is much narrower than at the base and tilted back. An example of this is the bell tower of Ivan the Great on Cathedral Square of the Moscow Kremlin, built in the 16th century. The effect of its “fall” is felt even in the photograph; Moreover, it was captured by the artist Giacomo Quarenghi, who painted the bell tower from nature and looked at it from another point.

One of the methods of eliminating the optical illusion associated with the perspective was suggested by the famous Italian Renaissance painter, the main architect of Florence, Giotto di Bondone (1267-1337). Designing the campanile (bell tower) at the Cathedral of Santa Maria del Fiore in Florence, he made it in the upper part much wider than at the base, in other words, resorted to the reverse perspective.

The ancient Greeks used this technique: rejected the elements of the upper part of the building from the vertical position. For example, the pediment was installed at an angle, tilting forward a little, just as paintings in museums are hung. And the sculptors made the figures that decorated the buildings more relief, and this smoothed out the visual effect of their reduction when viewed from the ground. Observation points were also taken into account: each statue was created taking into account the place that it was assigned to throughout the composition.

Sometimes architects used the illusion of perspective not to smooth, but, on the contrary, to enhance one or another visual effect. For example, in the portico (covered gallery in front of the entrance to the building) with a double row of columns, the internal columns were made thinner compared to those in front, visually removing them. This created the impression of a greater depth of space. Another original invention of the Greeks was that the internal colonnade in the temples, they sometimes erected a two-story. In the Parthenon, for example, this was done not so much for beauty, as for achieving the illusion of a greater height of the statue of the goddess Athena, installed in the sanctuary. Against the background of a two-story structure, it looked bigger than it is, and therefore it looked more solemn and majestic. In short, the system of optical corrections, invented by architects, once again demonstrates their highest skill in the complex art of architecture.

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* Irradiation – the visual perception of three-dimensional objects and flat figures on a contrasting background, during which an optical illusion occurs: the observed object appears to be of a different size than it actually is.